ABSTRACT
Objective:To explore the diagnostic value of ultrasound in posterior fossa anomalies (PFA) at 11-13 + 6 gestational weeks by measuring brainstem (BS), brainstem-to-occipital bone (BSOB) diameter and BS/BSOB ratio. Methods:A total of 209 normal fetuses (control group) were randomly selected from Beijing Obstetrics and Gynecology Hospital, Capital Medical University, between March 2018 and November 2021. Reference ranges for BS, BSOB diameter and BS/BSOB ratio were obtained on the mid-sagittal view of the fetal profile and the relationship of three parameters and crown-rump length (CRL) was investigated. The intra- and inter-observer reliabilities were determined by intraclass correlation coefficient (ICC) in 30 normal fetuses. Fourteen fetuses diagnosed with PFA in the same period including 10 cases of cystic posterior fossa malformations (cPFM) and 4 cases of open spine bifida (OSB) were retrospectively selected to compare BS, BSOB diameter and the BS/BSOB ratio with control group.Results:BS and BSOB diameters were successfully obtained in all control fetuses (100%), and the intra- and inter-observer reliabilities for BS and BSOB diameters were good (ICC=0.877, 0.846 and 0.939, 0.895). In the control group, BS and BSOB diameter linearly correlated with CRL ( r=0.867, 0.794; all P<0.001), while the BS/BSOB ratio was 0.75 (0.71, 0.79). There were significant differences of BSOB diameter and BS/BSOB ratio between control group and PFA group (all P<0.05). Except for one isolated vermian hypoplasia (VH), the BSOB diameters in 9 (90%) cases of cPFM were above the 95th percentile of the calculated normal range and were below the 5th percentile in 4(100%) cases of OSB.Except for one isolated VH, the BS/BSOB ratio in 9 (90%) cases of cPFM was below the 5th percentile of the calculated normal range. The BS/BSOB ratio in 4 (100%) cases of OSB was above the 95th percentile of the calculated normal range. Conclusions:The measurements of BS and BSOB diameter are feasible with good repeatability. Abnormal BSOB diameter and BS/BSOB ratio are suggestive for PFA. The posterior fossa of isolated VH can be normal in the first trimester.
ABSTRACT
El trabajo multidisciplinario de profesionales especializados hace que el seguimiento del embarazo y la prevención de riesgo consigan optimizar cada vez más los resultados en medicina materno-fetal. El mejoramiento progresivo en el cálculo del riesgo, con marcadores ecográficos y séricos ha permitido establecer con mayor precisión el diagnóstico de cromosomopatías y patologías fetales, entre ellas la espina bífida. Aunque la práctica más difundida del screening prenatal es su aplicación en el segundo trimestre, hoy existe más exactitud si se realiza en el primer trimestre de la gestación. La translucencia intracraneal es muy poco conocida a nivel mundial como marcador ecográfico. Para lo cual se propuso realizar la medición de la translucencia intracraneal en los fetos con embarazos entre 11-13 semanas + 6 días y correlacionarla con la aparición de espina bífida en el II trimestre del embarazo, durante el período mayo 2010-2011. Se realizó un diseño prospectivo, longitudinal, no probabilístico, donde la población estuvo representada por 1583 pacientes evaluadas en la Unidad de Perinatología de la Ciudad Hospitalaria "Dr. Enrique Tejera" de Valencia y la muestra constituida por 74 fetos de embarazos entre 11 y 13 semanas + 6 días. En 66,66% la translucencia intracraneal midió entre 2,1 y 3mm, sin evidencias ecográficas de anomalías de cabeza y columna en el II trimestre; 60.81% nació por cesárea; la relación femenino/masculino casi 1/1, 89.18%, con peso al nacer de 2500-4000g, 6.75% de recién nacidos pre término, y en éstos 80% de mortalidad. No se encontró espina bífida en los recién nacidos.
Pregnancy tracking and risk prevention through a multidisciplinary work of professionals increasingly optimizes outcomes in maternal-fetal medicine. The progressive improvement of risk calculation with ultrasound and serum markers has allowed the diagnosis of fetal chromosomal anomalies and pathologies more accurately, including spina bifida. Although prenatal screening is widely performed in the second trimester, it is more precise when done in the first trimester. Intracranial translucency is little known worldwide as an ultrasound marker. For this reason, measurement of intracranial translucency in fetuses between 11-13 weeks + 6 days was carried out, as well as its correlation with the occurrence of spina bifida in the second trimester of pregnancy, This prospective, longitudinal and non-probabilistic study done between May 2010 - 2011 had a population of 1583 patients evaluated in the Perinatology Unit at "Dr. Enrique Tejera" City Hospital in Valencia-Venezuela. The sample consisted of 74 fetuses between 11 and 13 weeks + 6 days. 66.66% intracranial translucency measured between 2.1 and 3 mm, without sonographic evidence of head and spine abnormalities in the second trimester; 60.81% were born by C-section; female / male ratio was almost 1 /1; 89.18% had a birth weight of 2500-4000g. 6.75% were preterm infants, with 80% mortality in this group. No newborns with spina bifida were found.